arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2008.00671eess.AS
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TutorNet:面向端到端语音识别的灵活知识提取

TutorNet: Towards Flexible Knowledge Distillation for End-to-End Speech Recognition

Ji Won Yoon, Hyeonseung Lee, Hyung Yong Kim, Won Ik Cho, Nam Soo Kim

摘要:

近年来,在开发端到端语音识别模型方面进行了大量的研究,这使得能够简化传统的流水线并实现有希望的结果。尽管端到端模型的性能有了显著的提高,但它们通常需要昂贵的计算成本才能显示出成功的性能。为了减少这种计算负担,知识蒸馏(KD),这是一种流行的模型压缩方法,已被用于将知识从深层和复杂的模型(教师)转移到浅层和简单的模型(学生)。之前的KD方法通常通过减少教师模型的每层宽度或层数来设计学生模型的架构。这种结构简化方案可能会限制模型选择的灵活性,因为学生模型结构应该与给定教师的模型结构相似。为了应对这一限制,我们提出了一种用于端到端语音识别的新KD方法,即TutorNet,它可以在隐藏表示级别和输出级别跨不同类型的神经网络传输知识。在具体实现上,首先在初始化阶段采用表示级知识提取(RKD),然后结合原始任务学习采用软最大级知识提取(SKD)。当学生用RKD训练时,我们使用帧加权来指出教师模型更关注的帧。通过在LibriSpeech数据集上的大量实验,验证了该方法不仅能够提取不同拓扑结构网络之间的知识,而且能够显著提高提取后学生的误词率(WER)性能。有趣的是,TutorNet允许学生模型在某些特定情况下超越教师的表现。

英文摘要:

In recent years, there has been a great deal of research in developing end-to-end speech recognition models, which enable simplifying the traditional pipeline and achieving promising results. Despite their remarkable performance improvements, end-to-end models typically require expensive computational cost to show successful performance. To reduce this computational burden, knowledge distillation (KD), which is a popular model compression method, has been used to transfer knowledge from a deep and complex model (teacher) to a shallower and simpler model (student). Previous KD approaches have commonly designed the architecture of the student model by reducing the width per layer or the number of layers of the teacher model. This structural reduction scheme might limit the flexibility of model selection since the student model structure should be similar to that of the given teacher. To cope with this limitation, we propose a new KD method for end-to-end speech recognition, namely TutorNet, that can transfer knowledge across different types of neural networks at the hidden representation-level as well as the output-level. For concrete realizations, we firstly apply representation-level knowledge distillation (RKD) during the initialization step, and then apply the softmax-level knowledge distillation (SKD) combined with the original task learning. When the student is trained with RKD, we make use of frame weighting that points out the frames to which the teacher model pays more attention. Through a number of experiments on LibriSpeech dataset, it is verified that the proposed method not only distills the knowledge between networks with different topologies but also significantly contributes to improving the word error rate (WER) performance of the distilled student. Interestingly, TutorNet allows the student model to surpass its teacher's performance in some particular cases.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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